Refrigeration



Sept. 6, 1938. A. T. LIGHT 20,848

REFRIGERATION I f Original Filed Oct. 25, 1927 4 Sheets-Sheet l ATTORNEYSept. 6, 1938. A. T. LIGHT Re. 20,848

REFRIGERAT ION Original Filed Oct. 25, 1927 4 Sheets-Sheet 2 AT TORNEY-A. T. LIGHT.

REFRIGERATION Sept. 6, 1938.

Oi-iginal Filed Oct. 25, 1927 4 Sheets-Sheet 5 Sept. 6, 1938. A; T.LIGHT Re. 20,848

REFRIGERATION Original Filed 001;. 25, 1927 4 Sheets-Sheet 4 j uzATTORNEY Reiasued Sept. 6, 1938 UNITED STATES PATENT OFFICE 20,848REFRIGERATION Original No. 1,866,988, dated July 12, 1932, Serial No.228,529, October 25, 1927.

Application for reissue July 11, 1934, Serial No. 734,698

30 Claims.

This invention relates to refrigeration, and

particularly to means for putting an evaporator quickly into and out ofoperation at will. The

invention has particular utility in the freezing of ice cream, and forpurpose of illustration will be described as so applied.

The invention aims to provide a means for freezing the ice creamexpeditiously by bringing the liquid refrigerant into direct contactwith the freezing cylinder, and to cause a rapid change in freezingconditions at the end of the freezing period by immediately removing theliquid refrigerant from contact with the freezing cylinder, therebyfacilitating the whipping process.

The device includes a. low pressure receiver into which the liquidrefrigerant is delivered from the condenser, suitable mechanism such asa pump for-circulating the refrigerant about the freezing cylinder anddraining means for quickly removing the refrigerant from contact withthe freezingcylinder when desired, and returning it to the receiver.

While preferred embodiments of the invention are herein disclosed forpurposes of illustration, .it should be understood that various changesmay be made in the structure without departing from the spirit and scopeof the invention as hereinafter set forth and claimed.

. In the drawings Flg. 1 is a front elevation of a freezer constructedaccording to this invention.

Fig. 2 is a side elevation of the machine of Fig. 1.

Fig. 3 is an enlarged section of mechanism.

Fig. 4 is an elevation driving mechanism.

Fig. 5 is a rear elevation of the driving mechanism.

Fig. 6 is a side elevation of another embodiment of the invention.

Fig. '7 15a sectionaldetail.

Referring to the drawings more particularly, the machine includes a baseIt], upon which are supported'the various parts of the freezer. Thefreezingcylinder i I (Fig. 4) is surrounded by the insulated casing l2,and the jacket space I3 lying between the cylinder II and the casing l2constitutes the evaporator.

In carrying out the objects of the invention any preferred volatileliquid refrigerant is brought into contact with the exterior of thefreezing cylinder II during the 'period during which the ice cream isbeing frozen in the cylinder. After the ice cream has reached a certainpart of the partly in section of the consistency it is desirable toprevent any further lowering of the temperature of the ice cream, andthen to continue to whip it with the beating elements until it hasattained the proper swell or overrun. During this whipping period thetemperature should not drop, but should remain practically stationary orshould rise slightly. In order to attain this end the invention providesfor removing the liquid refrigerant from contact with" the freezingcylinder during the whipping period.

One arrangement for handling the liquid refrigerant is illustrated inFigs. 1 and 2. This mechanism includes a tank or low pressure receiverit carried by the base Ill below the casing i2. A high pressure liquidrefrigerant supply line [5 carries the liquid refrigerant from anysuitable compressor and condenser, not shown, through strainer I6 andfloat valve I] to the receiver It. The float valve is arranged to shutoif the incoming supply whenever the liquid in receiver I4 reaches acertain level. A supply line l8 leads from the bottom of the receiver Hthrough a control valve Hi to the lower part of the evaporator I3. Apump 20, operated by a motor 2|, is interposed in the supply line [8 forpumping the liquid through line l8 and control valve l9 to theevaporator. A return line 22 runs from the top of the evaporator l3 backto the receiver It, thus completing a closed circuit which includes theevaporator and the-receiver.

The control valve I 9 is shown in detail in Fig. 3 and includes a casingprovided with a chamber 23 having a conical seat 24 at its upper end anda port 25 leading through one side. The moving element comprises abarrel member 26 which carries near one end a conical valve head 21which fits into the seat 24, and at its other end a disc 28 which fitsclosely in the chamber 23. A passage 29 leads through the center of thebarrel 26. 40 A drain connection 30 leads from port 25 to the returnline 22. The supply line I8 leads into the bottom of the chamber 23through the cover plate 3|.

The stirring elements within the freezing cylinder comprise a scraper 32which moves in one direction next to the inner wall of cylinder II,. andan inner beater 33 which moves in the opposite direction. These elementsare operated by mechanism now to be described.

The scraper 32 carries at its rear end a hollow shaft 34 which projectsthrough oneend of cylinder H and has a. sprocket 35 keyed thereto. Ashaft 36, connected with thebeater, extends through the shaft 34 and hasa sprocket 31 keyed thereon, the outer end of shaft 33 being supportedin a bearing 38 mounted on base I0. A motor 39, in the lower part ofbase III, has its shaft '40 provided with drive sprockets 4| and 42alined with sprockets 35 and 31 respectively. A sprocket chain 43extends around the sprockets 4| and 35 and is tightened by the idler 44.A second sprocket chain 45 has its upper end passed around the sprocket31 and its lower end passed around an idler 46 located below thesprocket 42, one side of chain 45 being partly wrapped around thedriving sprocket 42 as will be clear from Fig. 5. Because of thisarrangement, when the shaft 40 rotates in a clockwise direction, thesprocket 35 will rotate in the same direction, while the sprocket 31will rotate in a counter clockwise direction, and the beater and scraperwill therefore be rotated in opposite directions. This mechanismprovides a simple and direct drive and eliminates the large frictionlosses in-..

cident to the use of bevel gears, and other types of gear devices. Acasing '41 encloses the sprockets I5 and 21. l

The machine operates in the following, manner: 1

After the batch of cream has been placed in the cylinder II the motor 19is started, thereby putting the stirring elements into operation. At thesame time the motor 2| which drives pump is set into operation. Thispump draws the liquid refrigerant from the bottom of the receiver l4 anddischarges it into the chamber 23. The pressure created below the disc28 pushes the member 26 to its upper position illustrated in Fig. 3,shutting of! passage through pipe but permitting the liquid to flowthrough passage 29 and thence via line ID to the evaporator ll. When theevaporator becomes fllled,;liquid and vapor will pass through overflowline 22 back to receiver l4, and the pump 20 will keepcirculating therefrigerant through the evaporator in direct contact with the entireouter surface of cylinder l I, thereby bringing about a very rapid anduniform cooling of the batch in the derii.

A gas and liquid separator 48 is in communication with the upper part ofreceiver l4, and the suction line 49 of the compressor (not shown) leadsfrom the separator to carry 91! the evaporated refrigerant;

When the batch has been frozen to the desired consistency and it isdesired to whip the frozen cream, the motor 2| is stopped. This actionsteps the upward pressure against member 26 and permits it to fall tothe bottom of chamber 23, in which position it allows the refrigerant todrain from the evaporator l2 back to receiver l4 by way of the returnline 30. In this way the chamber I3 is quickly drained of liquidrefrigerant, and no further lowering of the temperature of the chargecan then take place. Meanwhile the motor 39 continues to run and thewhippers beat up the frozen cream for a period long enough to give thedesired overrun.

The tank l4 acts as a low pressure container in .which the liquidrefrigerant is kept under practically no pressure, and since it alwayscontains a level of refrigerant, the machine is always ready to startfreezing a fresh batch of cream as soon as it is placed in the cylinderH.

In this manner the liquid refrigerant is used over and over by beingcirculated between the low pressure container i4 and the refrigerationchamber l3, and only such refrigerant as va- 'p0rizes is carried oil tothe compressor. The

cylinfloat valve insures a certain level of liquid refrigerant in thecontainer at all times, but there is always enough free space in thecontainer l4 to permit all of 'the liquid in the refrigeration chamberii to flow back into the container.

It will be observed that the arrangement above described functions tomaintain the evaporator flooded when the pump is in operation and todrain it rapidly when the pump stops.

It will be evident that any suitable arrangement could be used tocirculate the refrigerant between the low pressure receiver and theevaporator, the essential requirements for ice cream freezing being thatthe liquid. be brought into direct contact with the freeflng cylinderduring the freezing period and be quickly withdrawn at the end of saidperiod.

Another arrangement for carrying out the process is shown in Fig. 6. Inthis case'the liquid refrigerant is pumped from the low pressurereceiver l4 through line 48' to the header 49' located in the evaporatorabove the cylinder II. The header is arranged-to spray the liquid overthe sides of the cylinder II for its entire length. The

liquid is permitted to collect in the refrigerant chamber until itreaches the height of the overflow pipe 5|) which conducts it back tothe low pressure receiver. A drain line 5|, controlled by a manuallyoperable-valve 52, leads from the bottom of the evaporator to the lowpressure receiver I4. During the freezing period the valve 52 is closedbut when it is desired to begin whipping, the pump is stopped and valve52 is opened, thereby quickly draining the liquid from the evaporator.

In the modified construction above described the evaporator is partiallyflooded. The location of the overflow pipe 50 determines the depth towhich it is flooded, and this may be arranged to suit particularconditions.

An important feature of theinvention is the ability to withdraw thevolatile liquid refrigerant from the evaporator quickly and certainly.Another important point is that the evaporator is flooded.- Because ofthe simplicity of the structure the use of a circulating pump andgravity return flow to accomplish the result just stated is preferred.The use of the by-passing return flow valve which allows the backwardflowfrom the evaporator to occur around the pump, is important, not onlybecause it allows displacement types of pump to be used, but alsobecause it gives a relatively rapid return flow. However, there arevarious ways in which the desired result can be' secured, and except asspecified in the claims, no necessary limitation to the particularstructure here illustrated is implied.

While the invention has its primary utility in the ice cream field, itis available for use in any fleld where a rapid suspension and aresumption of the evaporator action is desirable.

In certain of the-claims the word cylinder is used to describe thechamber in which the batch tobe frozen is contained during the freezingoperation. This is used in the sense in which it is used in the icecream industry without any implication of limitation to a true orapproximately cylindrical form of the chamber.

I claim:

1. An ice cream machine comprising a freezing cylinder, a refrigerationchamber associated with the cylinder, means for supplying liquidrefrigerant to the refrigeration chamber in direct contact with thecylinder during the freezing period, and means comprising a portion ofsaid first named means for discharging the liquid refrigerant from therefrigeratidn chamber to expedite the whipping operation.

2. An ice cream machine comprising a freezing cylinder, a refrigerationchamber associated with the cylinder, a low pressure container, meansfor supplying liquid refrigerant to the low pressure container, meansfor removing liquid refrigerant from the low pressure container andsupplying it to the refrigeration chamber in direct contact with thecylinder during the freezing period, and means comprising a portion ofsaid first named means for discharging the liquid refrigerant from therefrigeration chamber (and returning it to the low pressure container)to expedite the whipping operation.

3. An ice cream machine comprising a freezing cylinder, a refrigerationchambenassociated' with the cylinder, a low pressure container, a feedline adapted to carry liquid refrigerant to the low pressure container,an exhaust line adapted to carry vaporized refrigerant away from the lowpressure container, means for removing liquid refrigerant from the lowpressure container and supplying it to the refrigeration chamber indirect contact with the cylinder during the freezing period, and meanscomprising a portion of said first named means for discharging theliquid refrigerant from the refrigeration chamber (and returning it tothe low pressure container) to expedite the whipping operation.

4. An ice cream machine comprising a freezing cylinder, a refrigerationchamber associated with the cylinder, a low pressure container, a feedline adapted to carry liquid refrigerant to the low pressure container,a float valve in the feed line, an exhaust line adapted to carryvaporized refrigerant from the low pressure container, means forremoving liquid refrigerant from the low pressure container andsupplying it to the refrigeration chamber in direct contact with thecylinder during the freezing period, and means comprising a portion ofsaid first named means for discharging the liquid refrigerant from therefrigeration chamber (and returning it to the low pressure container)to expedite the whipping operation.

5. An ice cream machine comprising a freezing cylinder, a refrigerationchamber associated with the cylinder, a low pressure container adaptedto receive liquid refrigerant, a feed line adapted to carry liquidrefrigerant from the low pres sure container to the refrigerationchamber, a pump in the feed line, and a line comprising a portion ofsaid feed line for returning the liquid refrigerant from saidrefrigeration chamber to i the low pressure container.

6. An ice cream machine comprising a freezing cylinder, a refrigerationchamber associated with the cylinder, a low pressure container, a feedline adapted to carry liquid refrigerant to the low pressure container,a float valve in the feed line, an exhaust line adapted to carryvaporized refrigerant from the low pressure container, a pump lineadapted to carry liquid re frigerant from the low pressure container tothe refrigeration chamber, a pump in the pump line, and a return linecomprising a portion of said pump line for carrying the liquidrefrigerant back to the low pressure container.

7. An ice cream machine comprising a freezing cylinder, a refrigerationchamber associated with the cylinder, a low pressure container adaptedto receive liquid refrigerant, a feed line adapted to carry liquidrefrigerant from the low pres sure container to the bottom oftherefrigeration chamber, a return line for the refrigerant, a pressureoperated valve controlling a passage to the return line, a pump in thefeed line between the valve and the low pressure container, and anoverflow line extending from the top of the re frigeration chamber tothe low pressure container.

8. The combination of an ice cream freezer having an evaporator directlyassociated therewith; means for supplying volatile liquid refrigerant tothe evaporator; and means including a portion of the first named meansfor discharging liquid refrigerant from the evaporator.

9. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver forvolatile'liquid-refrigerant substantially devoid of heat exchangingrelation with said freezer; means affording a closed circuit'forrefrigerant from the receiver upward through said evaporator and back tothe receiver; and means operable at will for discharging liquidrefrigerant from the evaporator to the receiver.

10. The combination of an ice cream freezer having an evaporator in heatexchanging relationtherewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat exchanging relation withsaid freezer; means affording a closed circuit for refrigerant from thereceiver. upward through said evaporator and back to the receiver;poweractuated means for circulating liquid refrigerantthrough said circuit inthe direction stated; and means operable at will for terminating suchcirculation and discharging the liquid refrigerant from the evaporatorto the receiver.

11. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat exchangingrelation withsaid freezer; means affording a closed circuit for refrigerant from thereceiver upward through said evaporator and backto the receiver; andmeans operable at will for discharging liquid refrigerant from theevaporator to the receiver through a portion of said circuit.

12. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat exchanging relation withsaid freezer; means affording a closed circuit for refrigerant from thereceiver upward through said evaporator and back to the receiver; poweractuated means for circulating liquid refrigerant through said circui-tin the direction stated; and means operable at will for terminating suchcirculation and discharging the liquid refrigerant from the evaporatorto the receiver through a portion of said circuit.

13. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat exchanging relation withsaid freezer; means affording a closed circuit for refrigerant from thereceiver upward through said evaporator and back to the receiver; asuction connection leading from.the receiver; a supply line for liquidrefrigerant leading to said receiver; means responsive to the quantityofliquid in the receiver for controlling flow through said supply line;and means operable at will for discharging liquid refrigerant from saidevaporator to said receiver.

14. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat exchanging relation withsaid freezer; means affording a closed circuit for refrigerant from thereceiver upward through said evaporator and back to the receiver; poweractuated means for circulating liquid refrigerant through said circuitin the direction stated; a suction connection leading from the receiver;a supply line for liquid refrigerant-leading to said receiver; meansresponsive to the quantity'of liquid in the receiver for controllingflow through said supply line; and means operable at will forterminating such circulation and discharging the liquid refrigerant fromsaid evaporator to said receiver.

15. The combination of an ice cream freezer having an evaporator in heatexchanging relaopen when the pump is at rest.

16. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a receiver for volatile refrigerant,substantially devoid of heat exchanging relation with said freezer andlocated at a lower level than the evaporator; means affording a closedcircuit through said receiver -and'evaporator; means operable to causecirculation of refrigerant in said circuit; a drain connection from saidevaporator to said receiver; a normally open valve controlling saidconnection; and means actuated by flow in said circuit and operativelyconnected with said valve'to close the same when such flow occurs.

1']. The combination of an evaporator; a receiver for volatile liquidrefrigerant, located at a lower level than the evaporator andsubstantially out of heat exchanging relation with the spacerefrigerated by said evaporator; a pump serving to draw liquidrefrigerant from said receiver and deliver it to said evaporator; anoverflow connection leading from a point above the bottom of saidevaporator to said receiver; and means operative when the pump isinactive for drain ng said evaporator to said receiver.

18. The combination of an evaporator; a receiver for volatile liquidrefrigerant, located at a lower level than the evaporator andsubstantially out of heat exchanging relation with the spacerefrigerated by said evaporator; a pump serving to draw liquidrefrigerant from said receiver and deliver it to said evaporator; anoverflow connection leading from the top of said evaporator to saidreceiver; and means operative when the pump is inactive for drainingsaid evaporator to said receiver.

19. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat exchanging relation withsaid freezer; a suction connection in communication with saidevaporator; a liquid connection between said evaporator and receiver;and means operable at will to supply liquid refrigerant in quantity fromsaid receiver to said evaporator to sustain active re-' frigeration inthe evaporator, and to suspend said supply and return unevaporatedliquid refrigerant to said receiver to arrest such active refrigerationin the evaporator.

20. The combinationof an evaporator; a receiver for volatile liquidrefrigerant substantially devoid of heat exchanging relation with the,

space refrigerated by said evaporator, and located at a lower level thanthe evaporator; a

pump serving to draw liquid refrigerant from said receiver and todeliver it to said evaporator; an overflow connection leading from apoint above the bottom of said evaporator to said receiver; and valvemeans serving when open to drain said evaporator to said receiver.

21. The combination of an ice cream freezer having an evaporator in heatexchanging relation therewith; a low pressure receiver for volatileliquid refrigerant substantially devoid of heat the evaporator of liquidrefrigerant and suspend active refrigeration in the evaporator.

22. In apparatus of the class described, the combination of a container,a casing surrounding said container in spaced relation thereto, adistributor in the space between said casing and container, above thelatter, extending substantially from end to end thereof, a reservoir fora liquid refrigerant, means for conveying liquid refrigerant from saidreservoir to said distributor,

--and connections for permitting the gravity return of unevaporatedrefrigerant from said space to the reservoir, and the withdrawal fromsaid space and reservoir of evaporated refrigerant.

23. In apparatus of the class described, the combination of ahorizontal, closed container having a material inlet and a valvecontrolled material outlet, a casing surrounding said container inspaced relation thereto and closed at its opposite ends, a reservoir fora liquid refrlg erant below said casing, a pipe for supplyingrefrigerant tolsaid reservoir, a valve in said pipe,

means for controlling the operation of said valve, said controllingmeans including a float in said reservoir and operated by the rise andfall of the liquid level therein, whereby a substantially predeterminedsupply of refrigerant is maintained in said reservoir, a pipe .in the.space between said casing and container, above the latter and extendingfrom end to end thereof and formed with discharge ports for distributingthe refrigerant onto the walls of said container, to permit therefrigerant to flow downwardly over the walls thereof, means forconveying refrigerant from said reservoir to said pipe. and connectionsfor permitting the gravity return of unevaporated refrigerant from saidspace to the reservoir, and the withdrawal from said space and reservoirof evaporated refrigerant.

24. In apparatus of the class described, the combination of a container,a casing surroundsome ing said container in spaced relation thereto,means in the space between said casing and container, above the latter,for distributing liquid refrigerant onto said container, a reservoir fora liquid refrigerant, means for conveying liquid refrigerant from saidreservoir to said distributing means, and connections for permitting thegravity return of unevaporated refrigerant from said space to thereservoir,and the withdrawal from said space and reservoir of evaporatedrefrigerant.

25. The herein disclosed process of cooling material in a containerenclosed in a gas tight chamber, which consists in continuouslysupplying liquid refrigerant having a relatively low boiling point intosaid chamber above the container and causing downward flow of therefrigerant over the walls thereof and preventing formation of gaspockets on said walls while permitting the separation of gases from theliquid, discharging the unused liquid into a receiver, and conveyingaway the generated gases.

26. In apparatus of the class described, the combination of a closedcontainer, a casing surrounding said container in spaced relationthereto, a reservoir for liquid refrigerant below said casing, adischarge conduit leading from the lower portion of said casing to saidreservoir, means for conveying liquid refrigerant from said reservoir tothe space between said container and casing and discharging it onto theupper walls of said container, a pipe for supplying the liquidrefrigerant to said reservoir, a valve in said pipe outside the walls ofsaid reservoir, a float operated by the rise and fall of the refrigerantlevel in said reservoir, and operating connections between said floatand said valve for operating the latter.

2'1. The herein disclosed process of refrigerating material duringagitation thereof in a container surrounded by a closed chamber having adischarge opening which consists in agitating the material andsimultaneously supplying a liquid refrigerant having a relatively lowboiling point into the upper portion of said chamber and circulating itunder pressure over and in contact with the walls of the container anddischarging the unused portion of the refrigerant through said openingand utilizing the circulation of the refrigerant to remove from thecontainer walls gases generated by the transfer of heat from thematerial and simultaneously exhausting from the upper portion of thechamber the generated gases which become separated from the liquidrefrigerant. v

28. The herein disclosed process of refrigerating material in acontainer surrounded by a closed chamber having a discharge opening,which consists in supplying a liquid refrigerant having a relatively lowboiling point into the upper portion of said chamber and circulating itunder pressure over and in contact with the walls of the container anddischarging the unused portion of the refrigerant through said openingand utilizing the circulation of the refrigerant to remove from thecontainer walls gases generated by the transfer of heat from thematerial and simultaneously exhausting from the upper portion of thechamber the generated gases which become separated from the liquidrefrigerant.

29. The herein disclosed process of refrigerating material duringagitation thereof in a container surrounded by a closed chamber, whichconsists in supplying a liquid refrigerant having a relatively lowboiling point into the upper portion of said chamber and circulating itover and in contact with the walls of the container, collecting theunused portion of the refrigerant for re-circulating it over and incontact with the cylinder walls and utilizing the circulation of theliquid refrigerant to remove from the container walls gases generatedfrom the transfer of heat from the material and simultaneouslyexhausting from the upper portion of the chamber the generated gaseswhich become separated from the liquid, and then shutting off the supplyof the liquid refrigerant and continuing the agitation of the materialto effect whipping thereof.

' 30. The herein disclosed process of refrigerating material duringagitation thereof in a container surrounded by a closed chamber, whichconsists in supplying a liquid refrigerant having a relatively lowboiling point into said chamber and circulating it over and in contactwith the walls of the container, utilizing the circulation of the liquidover the container, walls to remove therefrom gases generated by thetransfer of heat from the material and simultaneously permitting theliquid and gases to separate and exhausting from the upper portion ofthe chamber the generated gases which become separated from the liquid.

ALBERT T. LIGHT.

